Assessment of the impact of application of single-photon emission computed tomography and SPECT-CT on lesion categorisation in bone scintigraphy : original research

Objectives: To assess initial experience with the use of a new single-photon emission computed tomography-computed tomography (SPECT-CT) in the evaluation of lesions. Methods: The folder number, radiopharmaceutical used and type of scan of patients examined with a new Siemens T6 SPECT-CT between 02 April 2016 and 31 December 2013 were retrieved. The number of 99mTc-MDP bone scans was sufficient for a detailed analysis. The scans were re-processed and reported by the observer before he was given any clinical information. Whole body planar, whole body planar plus SPECT and whole body planar plus SPECT-CT images were assessed successively in three separate sessions at least 2 weeks apart. At each session, the certainties of detection, localisation and categorisation of each lesion were recorded. Results: A total of 539 lesions were seen on the whole body, SPECT and computed tomography (CT) images in 133 patients. The whole body images showed no lesions in 3 patients and 378 lesions in 130 patients. SPECT detected 122 additional lesions in 79 patients. Thirty-nine (12.2%) lesions were seen only on CT in 32 (24.1%) patients. For the 261 lesions seen on the planar images in the SPECT field of view, lesion detection was definite in 233 (89.3%), localisation definite in 151 (57.9%) and categorisation definite in 123 (47.1%) lesions. On the SPECT, definite lesion detection, localisation and categorisation were recorded, respectively, for 259 (99.2%), 228 (87.4%) and 176 (67.4%) of the 261 lesions. Lesion detection, localisation and categorisation certainties were definite for 100%, 99.1% and 94.7% of the SPECT-CT lesions, respectively. Conclusion: SPECT markedly improves lesion detection and localisation, and CT enhances lesion categorisation.